US20200200617A1 - Pressure sensor and method for manufacturing pressure sensor - Google Patents

Pressure sensor and method for manufacturing pressure sensor Download PDF

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Publication number
US20200200617A1
US20200200617A1 US16/621,223 US201916621223A US2020200617A1 US 20200200617 A1 US20200200617 A1 US 20200200617A1 US 201916621223 A US201916621223 A US 201916621223A US 2020200617 A1 US2020200617 A1 US 2020200617A1
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Prior art keywords
pressure sensor
sensor
electrodes
sensor devices
conductive film
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US16/621,223
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English (en)
Inventor
Ryoichi Toyoshima
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Nippon Mektron KK
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Nippon Mektron KK
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Assigned to NIPPON MEKTRON, LTD. reassignment NIPPON MEKTRON, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TOYOSHIMA, RYOICHI
Publication of US20200200617A1 publication Critical patent/US20200200617A1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
    • G01L19/0627—Protection against aggressive medium in general
    • G01L19/0654—Protection against aggressive medium in general against moisture or humidity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes

Definitions

  • the present invention relates to a pressure sensor and a method for manufacturing the pressure sensor.
  • the pressure sensor for sensing pressure is used in various technical fields. Some types of pressure sensors are used in mobile terminals, robots and the like. It is desired that the pressure sensor for such an application can be installed in a relatively narrow range. That is, its footprint is desirably small. Further, the pressure sensor is required to detect a position where a pressure is received with high accuracy.
  • Known examples of pressure sensors are described in, for example, PATENT LITERATURE 1, PATENT LITERATURE 2, and PATENT LITERATURE 3.
  • a control device for a robot hand described in PATENT LITERATURE 1 has a gripping portion of workpiece in the robot and a pressure detection sensor used to detect a contact pressure with the workpiece.
  • PATENT LITERATURE 2 describes a seating sensor including a plurality of sensitive sensors connected in parallel.
  • PATENT LITERATURE 3 describes a membrane switch including a spacer provided between a pair of insulating films and has an open contact portion, and electrodes respectively formed on opposing surfaces of the opening. Further, it is described that a protruding portion is provided on an outer surface of at least one insulating film of the contact portion.
  • PATENT LITERATURE 1 JP-A-07-186078
  • PATENT LITERATURE 2 JP-A-2003-065865
  • the pressure sensor disclosed in PATENT LITERATURE 1 detects the contact pressure at a plurality of locations. Then, it is determined whether only a pressure value detected at any one of a plurality of contact pressures on a straight line in vertical, horizontal, and oblique directions is equal to or greater than a predetermined value. Therefore, the pressure sensor disclosed in PATENT LITERATURE 1 requires a plurality of pressure sensors respectively arranged in a plurality of directions. Therefore, an area required for installing the pressure sensors is increased. Further, according to an embodiment described in PATENT LITERATURE 2, the plurality of pressure sensors is provided in a passenger seat of the automobile. Then, influence of electrical resistance value detected by each of the pressure sensors on a total resistance is reduced.
  • the embodiment described in PATENT LITERATURE 2 is not intended to solve a problem related to the footprint of the pressure sensor, either.
  • the resistance value of the pressure sensor varies greatly even with a relatively small value of load. That is, the pressure sensor can measure a relatively small pressure with high sensitivity.
  • the pressure sensor has a disadvantage that a dynamic range of its measurement is narrow.
  • the pressure sensor according to the present embodiment has been developed in view of the above points. That is, the present disclosure relates to the pressure sensor capable of measuring the pressure in a wide range (measurement range) of measurable pressure and is suitable for reducing the footprint, and the method for manufacturing the pressure sensor.
  • a pressure sensor includes: a plurality of sensor devices; and a wiring sheet.
  • Each of the plurality of sensor devices includes electrodes and a conductive film disposed to face the electrodes.
  • the plurality of sensor devices is stacked in a direction in which the conductive film is disposed against the electrodes, and the wiring sheet includes a common input line for inputting electrical signals to the plurality of sensor devices, and a common output line for outputting the electrical signals from the plurality of sensor devices.
  • a method for manufacturing a pressure sensor includes forming on a wiring sheet, sensor devices each including a plurality of electrodes and a conductive film corresponding to at least one electrode of the plurality of electrodes, a common input line for inputting electrical signals to the sensor devices, and a common output line for outputting the electrical signals from the sensor devices, and stacking the sensor devices by folding the wiring sheet.
  • the pressure sensor capable of measuring a wide range of pressures within the measurement range and suitable for reducing the footprint, and a method for manufacturing the pressure sensor are provided.
  • FIG. 1 is a schematic cross-sectional view for explaining a pressure sensor according to an embodiment of the present disclosure.
  • FIG. 2( a ) is a schematic top view of a sensor device of the pressure sensor shown in FIG. 1 .
  • FIG. 2( b ) is a schematic cross-sectional view of the sensor device.
  • FIG. 3( a ) is a cross-sectional view of the sensor device of modification.
  • FIG. 3( b ) is a view for explaining folding of the sensor device of FIG. 3( a ) .
  • FIG. 3( c ) is a cross-sectional view of a configuration including the folded sensor device of FIG. 3( b ) .
  • FIG. 4 is a top view of the pressure sensor including stack circuits shown in FIGS. 1, 2 ( a ) and 2 ( b ), that are connected in parallel.
  • FIG. 5 is a diagram showing an equivalent circuit of the pressure sensor shown in FIG. 4 .
  • FIG. 6( a ) , FIG. 6( b ) , and FIG. 6( c ) are views for explaining a method for manufacturing the pressure sensor of the present embodiment.
  • FIG. 7( a ) , FIG. 7( b ) , and FIG. 7( c ) are views for explaining the method for manufacturing another pressure sensor of the present embodiment.
  • FIG. 8( a ) , FIG. 8( b ) , and FIG. 8( c ) are views for explaining another example of the method for manufacturing the pressure sensor of the present embodiment.
  • FIGS. 9( a ) and 9( b ) are views for explaining a modification 1 of the embodiment of the present disclosure.
  • FIGS. 10( a ) to 10( c ) are views for explaining a modification 2 of the embodiment of the present disclosure.
  • FIGS. 11( a ) and 11( b ) are diagrams for explaining an example of the present disclosure, and are the diagrams showing verification results of effects obtained by stacking the sensor devices.
  • FIGS. 12( a ) and 12( b ) are diagrams for explaining the example of the present disclosure, and are the diagrams showing the verification results of the effects when resistance characteristics of the stacked sensor devices are different to each other.
  • FIGS. 13( a ) to 13( c ) are diagrams for explaining the example of the present disclosure, and are the diagrams showing the verification results of the effects obtained by connecting the stacked sensor devices in parallel or in series.
  • a basic configuration of a pressure sensor of the present embodiment includes a sheet-like wiring board (hereinafter referred to as a wiring sheet) containing a flexible material processed into a sheet shape, and a wiring layer formed on the wiring sheet.
  • a wiring sheet a sheet-like wiring board
  • FIG. 1 is a schematic cross-sectional view for explaining a pressure sensor 1 of the present embodiment.
  • FIGS. 2( a ) and 2( b ) are schematic views for enlarging and explaining sensor devices U 1 and U 2 shown in FIG. 1 .
  • the wiring sheet of the pressure sensor is used as a reference (lowermost layer).
  • a direction from a side closer to the wiring sheet (a lower side of the drawing) to a side farther from the wiring sheet (an upper side of the drawing) is defined as an up-down direction.
  • the up-down direction does not necessarily coincide with an up-down direction of a product itself in which the pressure sensor is incorporated.
  • the sheet shape refers to a thin plate-like or film-like shape having a side surface that is sufficiently small so that the wiring sheet is flexible compared to a forming surface (an upper surface) of the wiring sheet on which the wiring layer is formed and a back surface (a lower surface) with respect to the upper surface. Whether it is a sheet shape does not depend only on thickness of the material.
  • FIG. 2( a ) is a schematic top view of the sensor device U 1 of the pressure sensor 1 .
  • FIG. 2( b ) is a schematic cross-sectional view of the sensor device U 1 or U 2 taken along an arrow line 2 b - 2 b in FIG. 2( a ) .
  • the pressure sensor 1 includes the sensor devices U 1 and U 2 .
  • Each of the sensor devices U 1 and U 2 includes two electrodes 19 a and 19 b that are spaced apart from each other by a predetermined distance, and a conductive film 15 that is disposed to face the electrodes 19 a and 19 b . Further, the sensor devices U 1 and U 2 are stacked on each other in a direction in which the conductive film 15 is disposed against the electrodes 19 a and 19 b .
  • the pressure sensor 1 also includes a wiring sheet 10 .
  • the wiring sheet 10 includes a common input line 21 that inputs electrical signals to the two sensor devices U 1 and U 2 , and a common output line 22 that outputs the electrical signals from a plurality of sensor devices U 1 and U 2 ( FIG. 4 ).
  • the sensor devices U 1 and U 2 have the same configuration.
  • the sensor devices U 1 and U 2 shown in FIGS. 2( a ) and 2( b ) are stacked on each other.
  • the input line 21 and the output line 22 are shared by them. Therefore, the stacked sensor devices constitute a circuit for outputting one detection signal (hereinafter referred to as a pressure-sensitive signal).
  • a circuit is hereinafter also referred to as a stack circuit S in the present embodiment.
  • a plurality of stack circuits S is provided on the wiring sheet 10 .
  • all of the sensor devices U 1 and U 2 formed on the wiring sheet 10 need not be limited to the stack circuit S. Elements having other configurations may be present on the wiring sheet 10 .
  • the electrodes 19 a and 19 b are formed on the wiring sheet of the pressure sensor 1 .
  • the pressure sensor 1 is constituted by the electrodes incorporated on the wiring sheet 10 . Therefore, the present embodiment has a configuration advantageous for reducing thickness of the stack circuit S.
  • a part of the plurality of sensor devices U 1 and U 2 includes a protrusion 17 a that overlaps at least a part of the electrodes 19 a and 19 b .
  • the protrusion 17 a exists on the sensor device U 1 side.
  • the sensor device U 1 is configured so that a load is concentrated on the electrodes 19 a and 19 b .
  • the sensor device U 1 includes the protrusion 17 a .
  • one protrusion 17 a is provided corresponding to all the plurality of sensor devices U 1 and U 2 which are stacked on each other.
  • a shape of the protrusion 17 a is not particularly limited. That is, the protrusion 17 a can be appropriately formed in any shape out of a quadrangular prism, a column, a substantially spherical body, and the like. Therefore, an end surface 170 of the protrusion 17 a (a lower end surface of the protrusion 17 a in FIG. 1 ; hereinafter referred to as a protrusion end surface) that transmits a pressing force from the device and the outside to the sensor device may also have any shape.
  • the protrusion 17 a of the present embodiment is a protrusion that protrudes upward from a base portion 17 b .
  • the base portion 17 b is a member generated when the protrusion 17 a is injection molded.
  • a member having a configuration including a combined protrusion 17 a and base portion 17 b is referred to as an electrode pressing material 17 .
  • the protrusion end surface 170 is a virtual surface corresponding to a boundary between the protrusion 17 a and the base portion 17 b .
  • the present embodiment is not limited to the embodiment in which the sensor devices U 1 and U 2 are stacked on each other so that directions thereof (directions from the electrode 19 toward the conductive film 15 ) are the same, as shown in FIGS. 1 and 2 ( b ).
  • the sensor devices U 1 and U 2 may be stacked so that the direction of the sensor device U 1 is opposite to the direction of the sensor device U 2 .
  • FIG. 3( a ) shows an embodiment in which the sensor devices U 1 and U 2 are stacked on each other so that the directions of the sensor device U 1 and the sensor device U 2 are opposite to each other.
  • the wiring sheet 10 is disposed inside them.
  • the sensor devices U 1 and U 2 may individually have the wiring sheet 10 .
  • the sensor devices U 1 and U 2 may share the single-layer wiring sheet 10 .
  • thickness of the pressure sensor can be reduced.
  • the pressure sensor 1 having a small thickness is advantageous for reducing its footprint by further stacking the sensor devices U 1 and U 2 .
  • FIG. 3( b ) is a view showing how the pressure sensor shown in FIG. 3( a ) is folded.
  • FIG. 3( b ) is a cross-sectional view of the pressure sensor manufactured by folding the pressure sensor shown in FIG. 3( a ) as shown in FIG. 3( b ) .
  • an insulating sheet 16 provided between the stacked conductive films 15 prevents conduction between two adjacent sensor devices U 1 .
  • the electrode pressing material 17 can be provided in any side of the upper and lower conductive films 15 which are the outermost layers.
  • the conductive film 15 may be disposed inside them.
  • the sensor devices U 1 and U 2 may be stacked so that the insulating sheet 16 is sandwiched between the sensor devices U 1 and U 2 from above and below.
  • the direction of the sensor device U 1 is opposite to the direction of the sensor device U 2 .
  • FIGS. 6( c ) and 8( c ) Such an embodiment will be described below with reference to FIGS. 6( c ) and 8( c ) .
  • the insulating sheet 16 is inserted between two conductive films 15 a and 15 b corresponding to the sensor devices U 11 and U 21 so that the two conductive films 15 a and 15 b are not electrically short-circuited.
  • FIG. 6( c ) the insulating sheet 16 is inserted between two conductive films 15 a and 15 b corresponding to the sensor devices U 11 and U 21 so that the two conductive films 15 a and 15 b are not electrically short-circuited.
  • insulating sheets 16 are respectively inserted between the conductive films 15 a and 15 b corresponding to the sensor devices U 11 and U 21 , and between the conductive films 15 c and 15 d corresponding to the sensor devices U 31 and U 41 .
  • the sensor device U 11 and the sensor device U 21 may be stacked so that a positional relationship between the wiring sheet 10 b and the conductive film 15 b is reversed from a configuration shown in FIGS. 1, 2 ( a ) and 2 ( b ) (the wiring sheet 10 below the conductive film 15 in FIGS. 1, 2 ( a ) and 2 ( b ) is above the conductive film 15 in FIG. 6( c ) ).
  • the positional relationship between the wiring sheet 10 b and the conductive film 15 b may be configured to be reversed from the configuration shown in FIGS. 1, 2 ( a ) and 2 ( b ). That is, the sensor device U 11 and the sensor device U 21 may be stacked so that the wiring sheet 10 below the conductive film 15 in FIGS. 1, 2 ( a ) and 2 ( b ) is above the conductive film 15 in FIG. 8( c ) . Further, similarly in FIG. 8( c ) , the sensor device U 31 and the sensor device U 41 may be stacked so that the positional relationship between the wiring sheet 10 d and the conductive film 15 d is reversed from the configuration shown in FIGS. 1, 2 ( a ) and 2 ( b ).
  • the one protrusion 17 a is provided corresponding to the sensor devices U 1 and U 2 .
  • the protrusion 17 a may be provided in each of the stacked sensor devices.
  • the protrusion 17 a may be provided outside the stacked sensor devices U 1 and U 2 .
  • the protrusion 17 a may be provided between the sensor devices U 1 and U 2 , that is, in the stack circuit S.
  • one protrusion 17 a of the sensor device U 1 or the sensor device U 2 is provided outside the stack circuit S.
  • the other protrusion 17 a may be provided inside the stack circuit.
  • the pressing force applied to the pressure sensor 1 is reliably concentrated on the electrodes 19 a and 19 b . Therefore, the protrusion 17 a can increase sensitivity of the pressure sensor 1 .
  • the protrusions 17 a When the protrusions 17 a are formed on the sensor devices of the stack circuits S that are stacked on each other, a part of the protrusion end surfaces 170 of the protrusions may be configured to have different sizes from the protrusion end surfaces 170 of other protrusions. In this way, a characteristic related to resistance of the sensor device constituting the stack circuit S will differ.
  • the characteristic related to the resistance of the sensor device refers to a physical or chemical characteristic that can affect an electrical resistance value of the sensor device among various parameters of the pressure sensor 1 . For example, it is assumed that the electrodes 19 a , 19 b and the conductive film 15 are pressed uniformly with a constant pressure stress (pressing force per unit area).
  • a contact area between the electrodes 19 a , 19 b and the conductive film 15 is increased or decreased.
  • the contact area is increased, electrical conduction between the electrodes 19 a and 19 b and the conductive film 15 is facilitated. Therefore, the resistance of the sensor device is reduced.
  • the contact area between the electrodes 19 a , 19 b and the conductive film 15 is decreased, the resistance of the sensor device is increased. Therefore, the contact area between the electrodes 19 a , 19 b and the conductive film 15 and the parameters that affect the contact area are examples of characteristics related to the resistance of the sensor device. Significance of changing the characteristics related to the resistance of the sensor devices U 1 and U 2 included in the stack circuit S in this way will be described below.
  • the pressure sensor 1 has an insulating layer 13 in addition to the above configuration.
  • the insulating layer 13 of the pressure sensor 1 shown in FIGS. 1, 2 ( a ) and 2 ( b ) covers substantially an entire surface of the wiring sheet 10 except for a part of formation region of the electrodes 19 a and 19 b , to protect the input line 21 and the output line 22 . At the same time, the insulating layer 13 improves its environmental resistance.
  • the insulating layer 13 is opened on the electrodes 19 a and 19 b .
  • An opening O 1 of the insulating layer 13 is shown in FIGS. 1, 2 ( a ) and 2 ( b ).
  • the electrodes 19 a and 19 b can be in contact with the conductive film 15 in a region of the opening O 1 .
  • An adhesive layer 11 is formed between the conductive film 15 and the insulating layer 13 .
  • the adhesive layer 11 maintains separation between the conductive film 15 and the electrodes 19 a and 19 b when no pressing force is applied to the pressure sensor.
  • the wiring sheet 10 of the present embodiment is a flexible and insulating film, and is a so-called flexible printed wiring board.
  • materials for the insulating film include polyethylene, polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer, polycarbonate, aramid resin, polyimide, polyimide varnish, polyamideimide, polyamideimide varnish, and flexible sheet glass.
  • the examples of the materials are not limited thereto. If high temperature durability in a usage environment of the pressure sensor 1 is taken into consideration, the material of the wiring sheet 10 is more preferably polycarbonate, aramid film, polyimide, polyimide varnish, polyamideimide, polyamideimide varnish, flexible sheet glass, or the like having high heat resistance.
  • the material of the wiring sheet 10 is still more preferably a polyimide film, a polyimide varnish film, a polyamideimide film, or a polyamideimide varnish film.
  • thickness of the wiring sheet 10 is not specifically limited, it can be set in a range of, for example, 12.5 ⁇ m or more and 50 ⁇ m or less. When the thickness of the wiring sheet 10 exceeds 12.5 ⁇ m, good durability is exhibited during a manufacturing process or use of the pressure sensor 1 . Further, when it is less than 50 ⁇ m, good flexibility is exhibited. Therefore, the wiring sheet 10 can be satisfactorily used by arranging or bending the wiring sheet 10 on a curved surface.
  • the wiring sheet 10 may be previously formed into a film shape. Or it may be formed by casting and applying an insulating varnish such as polyimide to a Cu foil or the like that is a material of the electrodes 19 a and 19 b .
  • the thickness of the wiring sheet 10 may be designed to be larger than that of the conductive film 15 from a viewpoint of improving both durability and high sensitivity characteristics of the pressure sensor 1 .
  • the electrodes 19 a and 19 b are a pair of electrodes arranged in parallel at a predetermined distance in a plane direction.
  • the electrodes 19 a and 19 b are formed on the wiring sheet 10 in a desired pattern shape.
  • the sensor devices U 1 and U 2 of the present embodiment individually have the wiring sheet 10 and the electrodes 19 a and 19 b . That is, the stack circuit S of the present embodiment shown in FIG. 2( b ) is configured to include two wiring sheets 10 and two conductive films 15 facing each other.
  • the electrodes 19 a and 19 b are respectively formed on the same surface side (an upper surface side in the drawing) of each of the wiring sheets 10 .
  • each of the electrodes 19 a and 19 b of the present embodiment has a rectangular shape when viewed from above. In addition, they are adjacently arranged in parallel at the predetermined distance. A combined resistance value of the electrodes 19 a and 19 b varies depending on a distance between the electrodes 19 a and 19 b .
  • the electrode 19 a and the electrode 19 b of the present embodiment are formed in the same shape and the same size. However, the present embodiment is not limited to this.
  • the electrode 19 a and the electrode 19 b may have different shapes. Or it may be similar and have different sizes.
  • the distance between the electrodes 19 a and 19 b is not particularly limited. The distance can be determined based on a distance between the electrodes 19 a , 19 b and the conductive film 15 . For example, when a distance A between the electrodes 19 a , 19 b and the conductive film 15 is 5 ⁇ m or more and 25 ⁇ m or less, the distance between the counter electrodes can be designed in a range of 10 ⁇ m or more and 500 ⁇ m or less. Thus, suitable pressure-sensitive characteristics and manufacturing stability can be obtained. At this time, a thickness of the electrodes 19 a and 19 b is preferably 9 ⁇ m or more and 20 ⁇ m or less.
  • the electrodes 19 a and 19 b are made of a conductive member.
  • the electrodes 19 a and 19 b are made of a low-resistance metal material.
  • surface resistivity of the electrodes 19 a and 19 b is designed to be smaller than that of the conductive film 15 .
  • the electrodes 19 a and 19 b are preferably formed from copper, silver, a metal material containing copper or silver, aluminum, or the like.
  • the material is not limited thereto. Further, form of the material can be appropriately determined by combining with a method for manufacturing the electrodes 19 a and 19 b in addition to foil, paste or the like.
  • the electrode 19 a and the electrode 19 b are connected to the input line 21 and the output line 22 formed on the wiring sheet 10 .
  • One end of the input line 21 is connected to a power source (not shown).
  • the other end of the input line 21 is connected to, for example, all of the sensor devices U 1 and U 2 formed on the wiring sheet 10 . With this connection, current or voltage is supplied to the sensor devices U 1 and U 2 .
  • the output line 22 is connected to a driver device (not shown) of the pressure sensor 1 .
  • the output line 22 is common to the sensor devices U 1 and U 2 constituting one stack circuit.
  • One pressure-sensitive signal is output from one stack circuit S. Therefore, the pressure-sensitive signal of the present embodiment is a combined value of the resistance values detected by the sensor devices U 1 and U 2 .
  • the input line 21 and the output line 22 may be formed only on one surface of the wiring sheet 10 . Or any or all of the input line 21 and the output line 22 may be drawn out through a through-hole (TH) to a surface opposite to a surface of the wiring sheet 10 on which the electrodes 19 a and 19 b are formed. The input line 21 and the output line 22 drawn out to the opposite surface may be drawn out again to the surface on which the electrodes 19 a and 19 b are formed through the through-hole (TH).
  • the wiring sheet 10 of the present embodiment may be a double-sided board on which the input line 21 and the output line 22 are arranged on both sides thereof. Or the wiring sheet 10 may be a single-sided board.
  • FIG. 3( b ) is a cross-sectional view of the sensor device according to a modification of the present embodiment which shows such a structure.
  • the wiring sheet 10 of the present modification including the sensor devices U 1 and U 2 may be stacked, for example, by being further folded to form a multilayer sensor device having four or more layers. According to the present modification shown in FIG. 3( b ) , the wiring sheet 10 can be reduced by one layer as compared with the embodiment shown in FIG. 2( b ) . Therefore, the pressure sensor 1 can be thinned
  • the insulating layer 13 is provided on the upper surface of the wiring sheet 10 provided with the electrodes 19 a and 19 b .
  • the insulating layer 13 forms a spacer for separating the electrodes 19 a and 19 b from the conductive film 15 by a predetermined distance A (see FIG. 1 ) on the electrodes 19 a and 19 b together with the opening O 1 so that at least a part of the electrodes 19 a and 19 b are in contact with the conductive film 15 .
  • the electrodes 19 a , 19 b and the conductive film 15 are separated from each other due to presence of the insulating layer 13 and the adhesive layer 11 .
  • the electrodes 19 a and 19 b are not conductive.
  • the pressing force required to bring the conductive film 15 into contact with the electrodes 19 a and 19 b is increased.
  • a deformation amount of the sensor devices U 1 and U 2 is reduced.
  • a resistance between the electrodes 19 a , 19 b and the conductive film 15 is increased. Therefore, the distance A between the electrodes 19 a , 19 b and the conductive film 15 is an example of characteristics related to the resistance of the sensor device.
  • An end portion of the insulating layer 13 on a side close to the opening O 1 may run on the electrodes 19 a and 19 b as shown in FIG. 1 .
  • the maximum height H of the insulating layer 13 is larger than a thickness of the insulating layer 13 in other regions sufficiently away from the electrodes 19 a and 19 b . Since the maximum height H of the insulating layer 13 is one of factors that determine the distance A between the electrodes 19 a , 19 b and the conductive film 15 , the maximum height H is also an example of characteristics related to the resistance of the sensor device.
  • An opening size of the opening O 1 is not particularly limited, and may be determined as appropriate without departing from the spirit of the present disclosure.
  • the opening O 1 can be set to have the longitudinal dimension of 1.5 mm and the lateral dimension of 1.05 mm.
  • the electrodes 19 a and 19 b are offset by 0.2 mm (0.1 mm on each side) with respect to the opening O 1 .
  • a solder resist can be used as the insulating layer 13 .
  • a material for the solder resist is not particularly limited.
  • the opening O 1 can be accurately formed.
  • the wiring sheet 10 can be coated so that the photosensitive material covers the electrodes 19 a and 19 b .
  • the preferred insulating layer 13 can be formed by exposing a predetermined portion to form the opening O 1 .
  • the opening O 1 of the present embodiment has a rectangular shape as shown in FIG. 2( a ) .
  • a shape of the opening O 1 can be appropriately designed in a circular shape, a polygonal shape, or an indefinite shape depending on the shapes of the electrodes 19 a and 19 b.
  • An example of the photosensitive material is an epoxy-based resin to which flexibility is appropriately added by a known means such as urethane modification.
  • the epoxy resin By using the epoxy resin, it is possible to form the insulating layer 13 having appropriate flexibility, and heat resistance that can be subject to a reflow process.
  • the conductive film 15 is laminated on the upper surface of the insulating layer 13 .
  • the insulating layer 13 and the conductive film 15 are joined to each other through the adhesive layer 11 .
  • any material such as a glue, an adhesive, a gluing sheet, or an adhesive sheet may be used, if the insulating layer 13 and the conductive film 15 can be joined.
  • the adhesive layer 11 has an opening having a shape substantially the same as that of the opening O 1 so that a contact resistance between the electrodes 19 a , 19 b and the conductive film 15 is not hindered.
  • the other may be bonded to the adhesive layer 11 while being aligned with the one of the insulating layer 13 and the conductive film 15 .
  • the conductive film 15 is a member that conducts between the electrodes 19 a and 19 b by contacting the electrodes 19 a and 19 b .
  • the conductive film 15 having a conductive function means that the conductive film 15 has electrical conductivity to the extent that the electrodes 19 a and 19 b can be energized through the conductive film 15 by pressing the conductive film 15 from the outside. Specifically, the conductive film 15 to which the pressing force is applied from the outside contacts over the electrode 19 a and the electrode 19 b . Thus, the electrode 19 a and the electrode 19 b are conducted.
  • the conductive film 15 in the present embodiment only needs to have the conductive function to the extent that the electrodes 19 a and 19 b are conducted by the conductive film 15 contacting the electrodes 19 a and 19 b . Therefore, the conductive film 15 may be, for example, a resin film containing carbon particles.
  • the conductive film 15 is given the conductive function by the carbon particles.
  • the resin film used as the conductive film 15 contains the carbon particles to the extent that the conductive function is exhibited.
  • the resin film is flexible. Thus, since the resin film itself has the conductive function, the conductive film 15 can be made thin. Further, the conductive film 15 having good flexibility can be obtained. As a result, the pressure sensor 1 having a large dynamic range can be obtained.
  • the resin film constituting the conductive film 15 can be appropriately formed by using a known resin without departing from the spirit of the present disclosure.
  • the resin include: polyester such as polyethylene terephthalate, polyethylene naphthalate, and cyclic polyolefin; polycarbonate; polyimide; polyamideimide; liquid crystal polymer and the like.
  • the conductive film 15 can be formed by mixing one or more resin materials among the above-described resins.
  • the carbon particles contained in the conductive film 15 are members for imparting conductivity to the conductive film 15 .
  • the carbon particle is a particulate carbon material.
  • Examples of carbon particles include one or a combination of two or more of carbon black such as acetylene black, furnace black (Ketjen Black), channel black and thermal black, and graphite.
  • carbon black such as acetylene black, furnace black (Ketjen Black), channel black and thermal black, and graphite.
  • the carbon particles are not limited to this example.
  • the content, shape and particle size of the carbon particles in the conductive film 15 are not particularly limited as long as they do not depart from the spirit of the present disclosure. They can be appropriately determined within a range in which the electrodes 19 a and 19 b are conducted depending on the contact resistance between the conductive film 15 and the electrodes 19 a and 19 b.
  • a thickness of the conductive film 15 is preferably 6.5 ⁇ m or more and 40 ⁇ m or less. When the thickness is 6.5 ⁇ m or more, the durability of the conductive film 15 is ensured. Further, when the thickness is 40 ⁇ m or less, initial stage detection sensitivity when the electrically conductive film 15 is pressed is good. In addition, a wide dynamic range can be secured. The thickness of the conductive film 15 can be measured using a general hide gauge, upright gauge, or other thickness measuring means.
  • the surface resistivity of the conductive film 15 is preferably 7 k ⁇ /sq or more and 30 k ⁇ /sq or less. When the surface resistivity is within the above range, the conductive film 15 has a small variation in sensor resistance when a large load is applied thereto. And high electrical reliability can be shown.
  • the surface resistivity of the conductive film 15 in a desired range can be adjusted by a blending amount of carbon particles contained in the conductive film 15 . In other words, the blending amount of the carbon particles contained in the conductive film 15 may be determined using as an index that the surface resistivity of the conductive film 15 falls within the above range.
  • the conductive film 15 may be adjusted so that surface roughness Rz of its surface facing the electrodes 19 a and 19 b is 0.10 ⁇ m or more and 0.50 ⁇ m or less. Thus, film formability of the conductive film 15 is improved. In addition, the detection sensitivity of the contact resistance is stabilized.
  • the surface roughness Rz of the conductive film 15 is measured by measurement using a general surface roughness meter or surface roughness analysis using a laser microscope.
  • Young's modulus of the conductive film 15 is preferably 5 GPa or less.
  • the conductive film 15 can be sufficiently flexible.
  • change in the contact resistance accompanying increase in the pressing force applied to the conductive film 15 can be well quantified in the above-described preferred range of the predetermined distance A and the opening size of the opening O 1 .
  • the method for producing the resin film containing carbon particles is not particularly limited.
  • a carbon particle-containing resin film can be produced by film-forming a composition obtained by appropriately kneading a mixture of one or more resins as raw materials and the carbon particles.
  • the conductivity, the surface resistivity, and the surface roughness of the conductive film 15 described above are parameters that affect a magnitude of the resistance value when the conductive film 15 contacts the electrodes 19 a and 19 b . Therefore, all are examples of characteristics related to the resistance of the sensor device. Further, when the thickness or Young's modulus of the conductive film 15 is large, displacement of the conductive film 15 when the predetermined pressing force is applied to the pressure sensor 1 is small. Therefore, as a result of the conductive film 15 being difficult to contact the electrodes 19 a and 19 b , the resistance of the sensor device is increased. Thus, these parameters are also examples of characteristics related to the resistance of the sensor device.
  • the electrode pressing material 17 is constituted by the protrusion 17 a and the base portion 17 b as described above.
  • the protrusion 17 a and the base portion 17 b are integrally formed of the same material, for example, by injection molding.
  • the base portion 17 b is formed of a molten material for forming the protrusion 17 a in the injection molding. Therefore, when the protrusion 17 a can be directly formed on the conductive film 15 , the electrode pressing material 17 does not include the base portion 17 b .
  • the material of the electrode pressing material 17 can be appropriately selected without departing from the spirit of the present embodiment. For example, a rubber material having a rubber hardness of 20 or more and 80 or less or a plastic material having a relatively low hardness is used.
  • the rubber material examples include natural rubber, acrylic rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, nitrile isoprene rubber, and silicon rubber. It is also possible to consider polyvinyl alcohol, ethylene-vinyl acetate copolymer, and the like as the plastic material.
  • the protrusion 17 a may have any shape.
  • the protrusion 17 a preferably has a shape and area suitable for the protrusion end surface 170 to concentrate the load on the electrodes 19 a and 19 b .
  • the protrusion end surface 170 preferably has a size that overlaps the opening O 1 and enters into the opening O 1 .
  • the pressure sensor 1 described above operates as follows. Electric power is supplied to the sensor devices U 1 and U 2 of the pressure sensor 1 through the input line 21 . Since the electrodes 19 a and 19 b are separated from each other, when the pressing force is not applied to the pressure sensor 1 , the electrodes 19 a and 19 b are not electrically conducted. When the pressing force is applied from above the pressure sensor 1 , the pressing force acts on both of the stacked sensor devices U 1 and U 2 . In the sensor devices U 1 and U 2 , the conductive film 15 is pushed downward by the protrusion 17 a . The pushed conductive film 15 contacts the electrodes 19 a and 19 b exposed from the opening O 1 .
  • the conductive film 15 and the electrodes 19 a , 19 b are in contact with each other, so that the electrodes 19 a and 19 b are conducted. Then, the electrical signal is output from the output line 22 to the driver device (not shown).
  • the driver device determines that the pressure sensor 1 has been turned on when the output detection signal becomes greater than or equal to a predetermined threshold value. And a magnitude of the detected pressure is determined by the magnitude of the detection signal after the pressure sensor 1 has been turned on.
  • the magnitude of the electrical signal output from the pressure sensor 1 varies depending on the area where the electrodes 19 a and 19 b contact the conductive film 15 . Therefore, when the conductive film 15 is strongly pressed against the electrodes 19 a and 19 b , the contact area increases, so that the resistance value decreases. When the electrical signal increases, it is determined that a strong pressure is applied to the sensor devices U 1 and U 2 .
  • the sensor devices U 1 and U 2 that are stacked on each other in a pressure application direction constitute the stack circuit.
  • the contact area between the electrodes 19 a , 19 b and the conductive film 15 of the sensor device U 1 to which the pressing force is transmitted first, and the contact area between the conductive film 15 and the electrodes 19 a , 19 b of the sensor device U 2 may be different.
  • the combined resistance of the sensor device U 1 and the sensor device U 2 includes a low resistance component and a high resistance component. Therefore, in the pressure sensor 1 , the electrical signal changes in a wider range depending on the pressure than when the pressure is applied to a sensor device that is not stacked (hereinafter referred to as a single sensor device).
  • the present embodiment described above can provide a wide-range pressure sensor with a wide pressure measurement range.
  • the stacked sensor devices included in the stack circuit S may be configured such that some of them have characteristics different from the characteristics related to the resistance of other sensor devices.
  • a relatively large electrical signal is output from the sensor device having a relatively low resistance in the stack circuit S.
  • a relatively small electrical signal is output from the sensor device having a relatively high resistance.
  • the large electrical signal starts to be output at a relatively low pressure. Therefore, an initial sensitivity of the pressure sensor 1 can be increased.
  • the small electrical signal output from the sensor device having the high resistance changes until after the large electrical signal does not change.
  • a combined value of the large and small electrical signals is output as a pressure detection signal. Therefore, it is possible to realize a wide-range pressure sensor 1 that can measure a wide range from low pressure to high pressure.
  • a method for changing the characteristics related to the resistance of the sensor device includes, for example, changing an area of the electrode that can be in contact with the conductive film. That is, a part of the stacked sensor devices used in the present embodiment may be configured such that the area of the electrode that can be in contact with the conductive film 15 is different from that of other sensor devices. As a configuration for changing the area of the electrode that can be in contact with the conductive film 15 , for example, it is conceivable to change the opening area of the opening O 1 between the sensor devices included in the stack circuit S. Further, it is also conceivable to change the areas themselves of the electrodes 19 a and 19 b.
  • a range where a concentrated load is applied between the conductive film 15 and the electrodes 19 a , 19 b may be different between the sensor devices.
  • a size of the protrusion end surface 170 of a part of the protrusions 17 a can be designed to be different from the size of the protrusion end surface 170 of the protrusions 17 a of other sensor devices. It is assumed that the pressing force from the outside applied to the protrusion 17 a is constant. In this case, the pressing force is dispersed by providing the protrusion 17 a having a large area of the protrusion end surface 170 .
  • the resistance between the electrodes 19 a , 19 b and the conductive film 15 is increased.
  • the protrusion 17 a having a small area of the protrusion end surface 170 the pressing force from the outside is concentrated.
  • the resistance between the electrodes 19 a , 19 b and the conductive film 15 is reduced. Therefore, the relatively small electrical signal is output from the sensor device corresponding to the large protrusion end surface 170 .
  • the relatively large electrical signal is output from the sensor device corresponding to the small protrusion end surface 170 . Therefore, a parameter of the area of the protrusion end surface 170 is an example of characteristics related to the resistance of the sensor device.
  • the large electrical signal corresponding to the small protrusion end surface 170 starts to be output at a relatively low pressure. Therefore, the initial sensitivity of the pressure sensor 1 can be increased. Further, the small electrical signal output from the sensor device corresponding to the large protrusion end surface 170 changes until after the large electrical signal does not change. Therefore, by making the areas of the protrusion end surfaces 170 different from each other, the combined value of the large and small electrical signals is output as the pressure detection signal. As a result, according to the present embodiment, it is possible to realize the wide-range pressure sensor 1 that can measure the wide range from low pressure to high pressure.
  • the configuration for changing the characteristics related to the resistance of the sensor device in the stack circuit S is not limited to changing the area of the protrusion end surface 170 .
  • the thickness, the surface roughness, electrical resistance profile (how to change) or the like of the conductive film 15 can be changed. In this way, it is conceivable to change the characteristics related to the resistance of the sensor device. Further, in the present embodiment, for example, it is conceivable to change the characteristics related to the resistance of the sensor device by changing the thickness, hardness or the like of the protrusion 17 a.
  • FIG. 4 is a top view showing the pressure sensor 1 of the present embodiment including the plurality of stack circuits shown in FIGS. 1, 2 ( a ) and 2 ( b ), that is connected in parallel.
  • FIG. 5 is a diagram showing an equivalent circuit of the pressure sensor 1 shown in FIG. 4 .
  • the illustrated pressure sensor 1 includes the plurality of sensor devices.
  • the stacked sensor device U 11 and the sensor device U 21 form a stack circuit S 1 .
  • the sensor device U 12 and the sensor device U 22 constitute a stack circuit S 2 .
  • the sensor device U 13 and the sensor device U 23 constitute a stack circuit S 3 .
  • a pair of sensor devices included in each stack circuit is connected in parallel to each other. According to such a configuration, in the present embodiment, a ratio of resistance characteristic of each sensor device constituting the stack circuit to the combined resistance is reduced. Thus, the electrical signal output from the stack circuit can be changed gently.
  • the stack circuit when the stack circuit includes the plurality of sensor devices having different resistance characteristics, the stack circuit can be designed such that the combined resistance changes continuously.
  • the stack circuit S 1 to a stack circuit S 8 are connected in parallel to each other.
  • the driver device (not shown) can obtain the detection signal of the pressure from each of the stack circuits.
  • the driver device may include the same number of input channels as the number of stack circuits. Or the driver device may include fewer input channels than the number of stack circuits.
  • the driver device may be designed to sequentially and repeatedly obtain detection signals output from the stack circuits at a frequency of, for example, about 300 Hz.
  • FIG. 6( a ) , FIG. 6( b ) , and FIG. 6( c ) are views for explaining a method for manufacturing the pressure sensor of the present embodiment.
  • FIG. 6( a ) is a top view of a pressure sensor member 100 .
  • the pressure sensor member 100 has the stack circuits S 1 to S 8 on the wiring sheet 10 .
  • Each of the stack circuit S 1 to the stack circuit S 8 includes paired two sensor devices such as the sensor devices U 11 and U 21 , sensor devices U 12 and U 22 , and the like.
  • the sensor device includes the electrodes 19 a and 19 b and the conductive film 15 disposed to face the electrodes 19 a and 19 b .
  • the pressure sensor member 100 includes the common input line 21 that inputs the electrical signals to the sensor devices U 11 , U 21 , and the like, and the common output line 22 that outputs the electrical signals from the sensor devices U 11 , U 21 , and the like.
  • the method for manufacturing the pressure sensor member 100 includes a process for forming on the wiring sheet 10 , the electrodes 19 a and 19 b , the conductive film 15 disposed facing the electrodes 19 a and 19 b , the common input line 21 for inputting the electrical signals to the sensor devices U 11 , U 21 , and the like, and the common output line 22 for outputting the electrical signals from the sensor devices U 11 , U 21 , and the like.
  • the electrodes 19 a and 19 b of the sensor devices U 11 and U 12 are arranged facing each other inwardly with the conductive film 15 therebetween.
  • the insulating sheet 16 is disposed on the entire surface between the conductive films 15 so that the two conductive films 15 are not electrically short-circuited.
  • the insulating sheet 16 can be made of the same material as the wiring sheet 10 described above, such as polyimide or polyamideimide.
  • the wiring sheet 10 and the insulating sheet 16 may be made of the same material or different materials.
  • the pressure sensor member 100 includes sensor devices U 11 to U 18 and sensor devices U 21 to U 28 constituting the stack circuit S 1 to the stack circuit S 8 .
  • through-holes h 1 and h 2 for electrically conducting front and back of the wiring sheet 10 are formed in the wiring sheet 10 .
  • the both surfaces of the wiring sheet 10 and inner surfaces in a thickness direction in the through-holes h 1 and h 2 are made conductive by plating or the like.
  • the front and back of the wiring sheet 10 can be made conductive.
  • an etching resist film is laminated on the wiring sheet 10 .
  • an etching mask having a pattern including the input line 21 , the output line 22 , and the electrodes 19 a and 19 b is formed on the wiring sheet 10 .
  • plating foil that is not covered with the etching mask is removed from the wiring sheet 10 by etching the plating foil using the etching mask as a mask.
  • the etching mask is peeled off after completing etching of the plating foil.
  • a cover film is laminated on a formation surface of the input line 21 and output line 22 in the wiring sheet 10 .
  • a soldering resist is printed on the formation surface, and this is exposed and developed, to form the insulating layer 13 .
  • a wiring protective layer can be formed by the above steps. Then, surfaces of the electrodes 19 a and 19 b facing the conductive film 15 are plated with nickel, gold or the like. Further, in the present embodiment, the conductive film 15 is bonded to the insulating layer 13 using the adhesive layer 11 .
  • the pressure sensor member 100 is completed through the above steps.
  • the method for manufacturing the pressure sensor of the present embodiment includes a step of stacking the sensor devices U 11 and U 21 by folding the pressure sensor member 100 which is the wiring sheet 10 that has undergone the above steps.
  • FIG. 6( b ) and FIG. 6( c ) are views for explaining the above steps.
  • FIG. 6( b ) is a perspective view of the pressure sensor member 100 in a process of being folded
  • FIG. 6( c ) is a schematic view of a cross-section obtained when the folded pressure sensor member 100 is cut on the sensor devices U 11 and U 12 in a direction perpendicular to a line L 1 in FIG. 6( a ) .
  • one side (a lower side in FIG.
  • the plurality of sensor devices included in each of the stack circuits is individually arranged in each of the partial region 10 a and the partial region 10 b by one.
  • the sensor device U 21 out of the two sensor devices U 11 and U 21 included in the leftmost stack circuit S 1 is disposed in the partial region 10 a .
  • the sensor device U 11 is disposed in the partial region 10 b.
  • the through-holes h 1 and h 2 are respectively formed in the partial regions 10 a and 10 b .
  • the through-holes h 1 and h 2 are formed at positions where they overlap each other when the wiring sheet 10 is folded along the line L 1 . Specifically, distances from centers of the through-holes h 1 and h 2 to the line L 1 are equal to each other. Further, an arrangement direction of the through-holes h 1 and h 2 is perpendicular to the line L 1 .
  • the pressure sensor member 100 is folded in a width direction thereof along the line L 1 .
  • two sensor devices for example, the sensor devices U 11 and U 21 ) in each (for example, the stack circuit S 1 ) of the plurality of stack circuits are stacked on each other.
  • the stack circuit for example, the stack circuit S 1
  • the pressure sensor member 100 is folded along the line L 1 so that formation surfaces of the sensor devices U 11 and U 21 are on its inside. Therefore, the stacked sensor devices U 11 and U 21 are arranged so that the conductive films 15 overlap each other as shown in FIG. 6( c ) .
  • the pressure sensor is completed by bonding the electrode pressing material 17 to one wiring sheet 10 of the sensor devices U 11 and U 21 .
  • the plurality of sensor devices can be formed at once and stacked on each other. Therefore, the process can be simplified. Further, a configuration in which the electrodes 19 a and 19 b are directly formed in the wiring sheet 10 is advantageous in reducing the thickness of the pressure sensor.
  • the present embodiment is not limited to folding the pressure sensor member 100 so that the formation surfaces of the sensor devices U 11 and U 21 are on the inside. In the present embodiment, the pressure sensor member 100 may be folded so that the formation surfaces of the sensor devices U 11 and U 21 are on the outside. In this case, the sensor devices U 11 and U 21 are stacked on each other so that the wiring sheets 10 overlap each other.
  • the present embodiment is not limited to providing the electrode pressing material 17 on one side of the stack circuit.
  • the electrode pressing material 17 may be formed on both sides of the stack circuit.
  • the sensor device may be stacked by folding the pressure sensor member 100 after providing the electrode pressing material 17 on the sensor device.
  • FIG. 7( a ) , FIG. 7( b ) , and FIG. 7( c ) are other views for explaining the method for manufacturing the pressure sensor of the present embodiment.
  • FIG. 7( a ) is a top view of the pressure sensor member 100
  • FIGS. 7( b ) and 7( c ) are views for explaining a process of stacking the sensor devices U 11 and U 21 by folding the pressure sensor member 100 .
  • FIG. 7( b ) is a cross-sectional view of the pressure sensor member 100 taken along an arrow line b-b shown in FIG. 7( a ) .
  • FIG. 7( b ) is a cross-sectional view of the pressure sensor member 100 taken along an arrow line b-b shown in FIG. 7( a ) .
  • FIG. 7( c ) is a view showing a state in which the sensor devices are stacked on each other by folding the pressure sensor member 100 shown in FIG. 7( b ) in a direction of an arrow line c in FIG. 7( b ) .
  • the pressure sensor member 100 is valley-folded at the line L 1 .
  • the pressure sensor member 100 is folded to form a mountain at the line L 1 .
  • the sensor device U 11 and the sensor device U 12 are stacked on each other so that their conductive films 15 are all disposed inside the wiring sheet 10 .
  • the pressure sensor shown in FIG. 7( c ) the sensor device U 11 and the sensor device U 12 are stacked on each other so that their conductive films 15 are all disposed outside the wiring sheet 10 .
  • the pressure sensor of FIG. 7( c ) is different from the pressure sensor of FIG. 6( c ) .
  • FIG. 8( a ) , FIG. 8( b ) , and FIG. 8( c ) are views for explaining an example in which the pressure sensor member 101 is folded three times in a bellows shape.
  • FIG. 8( a ) is a top view of the pressure sensor member 101 .
  • FIG. 8( b ) is a perspective view of the pressure sensor member 101 in the process of being folded.
  • FIG. 8( a ) is a top view of the pressure sensor member 101 .
  • FIG. 8( b ) is a perspective view of the pressure sensor member 101 in the process of being folded.
  • FIG. 8( c ) is a schematic view of a cross-section obtained by cutting the folded pressure sensor member 101 in a direction perpendicular to the line L 1 in the drawing and at a position passing through the sensor devices U 11 , U 21 , U 31 , U 41 .
  • the pressure sensor member 101 shown in FIG. 8( a ) includes 32 sensor devices U 11 to U 18 , U 21 to U 28 , U 31 to U 38 , and U 41 to U 48 .
  • the pressure sensor member 101 is folded along each of the three lines L 1 , L 2 , and L 3 . At this time, in the present embodiment, the pressure sensor member 101 is valley-folded along the line L 1 .
  • the sensor device U 11 and the sensor device U 21 are stacked on each other.
  • the pressure sensor member 101 is mountain-folded along the line L 2 .
  • the sensor device U 11 and the sensor device U 41 are stacked on each other.
  • the pressure sensor member 101 is valley-folded along the line L 3 .
  • the sensor device U 41 and the sensor device U 31 are stacked on each other.
  • partial regions 10 a to 10 d four regions partitioned by the lines L 1 to L 3 are referred to as partial regions 10 a to 10 d .
  • a region on one side of the line L 1 (a lower side in FIG. 8( a ) ) is referred to as the partial region 10 a .
  • a region surrounded by the lines L 1 and the line L 2 is referred to as the partial region 10 b .
  • a region surrounded by the line L 2 and the line L 3 is referred to as the partial region 10 c .
  • a region on the other side (an upper side in FIG. 8( a ) ) of the line L 3 is referred to as the partial region 10 d .
  • the plurality of sensor devices respectively included in the stack circuits is respectively arranged in one and the other of the two partial regions adjacent to each other and partitioned by one of the lines L 1 to L 3 , out of the partial regions 10 a to 10 d .
  • the sensor devices U 21 and U 11 are respectively arranged in the partial regions 10 a and 10 b partitioned by the line L 1 .
  • the sensor devices U 41 and U 31 are respectively arranged in the partial regions 10 c and 10 d partitioned by the line L 3 .
  • the partial regions 10 a to 10 d respectively have through-holes h 1 to h 4 penetrating the wiring sheet corresponding to the partial regions.
  • the through-holes h 1 to h 4 are formed at positions where they overlap each other when the wiring sheet 10 is folded along the lines L 1 to L 3 . Specifically, distances from centers of the through-holes h 1 and h 2 to the line L 1 are equal to each other. The distances from the centers of the through-holes h 1 and h 4 to the line L 2 are also equal to each other. Further, the distances from the centers of the through-holes h 3 and h 4 to the line L 3 are also equal to each other.
  • an arrangement direction of the through-holes h 1 to h 4 is perpendicular to the lines L 1 to L 3 that are parallel to each other.
  • the instrument such as the pin (not shown) can be inserted into the through-holes h 1 to h 4 .
  • the partial regions 10 a to 10 d can be suppressed from deviating from each other.
  • the present embodiment is not limited to a configuration including the sensor devices that are stacked on each other by folding the pressure sensor members 100 and 101 .
  • the input lines 21 or the output lines 22 may be connected to each other through the through-hole h 1 and the like.
  • one electrode pressing material 17 can be disposed corresponding to the plurality of stack circuits S arranged in the plane direction.
  • the plurality of sensor devices is stacked in the direction in which the conductive film is disposed against the electrodes of the sensor device. This is suitable for reducing the footprint of the pressure sensor.
  • a signal corresponding to a voltage drop caused by the combined resistance of the plurality of sensor devices can be output as the pressure detection signal. Therefore, the signal corresponding to the voltage drop caused by the combined resistance of the resistance value detected by each sensor device can be output as the detection signal. In this way, a wide range of pressures from a relatively low pressure to a relatively high pressure can be detected.
  • the entire pressure sensor 1 can be made thinner than a known configuration including, for example, mounted components such as tact switches or the like stacked in the thickness direction.
  • the sensor devices are stacked by folding the formed pressure sensor members 100 and 101 .
  • the number of electrical connection points can be reduced.
  • a degree of freedom in design can be increased.
  • the present embodiment is not limited to the embodiments described above.
  • the insulating layer 13 is not limited to an insulating layer formed to partially overlap peripheral edges of the electrodes 19 a and 19 b .
  • offsets may be provided between the peripheral edges of the electrodes 19 a , 19 b and the insulating layer 13 .
  • an opening O 2 of the insulating layer 13 is designed to be slightly larger than the peripheral edges of the electrodes 19 a and 19 b .
  • a dot pattern is added for convenience to a formation region of the insulating layer 13 in FIG. 9( a ) as in FIG. 2( a ) .
  • the electrodes 19 a and 19 b are entirely separated from the insulating layer 13 in an adjacent arrangement direction (a left-right direction in FIGS. 9( a ) and 9( b ) ). As shown in FIG. 9( a ) , in a direction perpendicular to the arrangement direction (the up-down direction in FIG. 9( a ) ), a part of end portions of the electrodes 19 a and 19 b may overlap the insulating layer 13 and be covered therewith. According to Modification 1 described above, it is possible to suppress variations in characteristics of the sensor device due to positional deviation between the opening O 1 and the electrodes 19 a , 19 b.
  • the present embodiment is not limited to a configuration including the rectangular electrodes 19 a and 19 b that are adjacently arranged in parallel with a predetermined distance as shown in FIG. 2( a ) .
  • the electrodes may include a first electrode and a second electrode, and the first electrode and the second electrode may be separated from each other and have a shape that can be fitted to each other.
  • the shape that can be fitted to each other means that all straight lines passing through an envelope region of the first electrode and the second electrode (the smallest rectangular region including the first electrode and the second electrode) intersect at least one of the first electrode and the second electrode.
  • FIGS. 10( a ), 10( b ), and 10( c ) are views for explaining the electrodes of the second modification.
  • a first electrode 82 a and a second electrode 82 b of an electrode 82 shown in FIG. 10( a ) have a comb-teeth shape mating with each other.
  • a first electrode 83 a and a second electrode 83 b of an electrode 83 shown in FIG. 10( b ) have a spiral shape mating with each other.
  • the first electrode 83 a and the second electrode 83 b of the electrode 83 shown in FIG. 10( c ) are arranged concentrically with each other.
  • one of the first electrode 83 a and the second electrode 83 b may have a circular shape, and the other may have a ring shape surrounding the circular shape with a predetermined distance.
  • the circular shape includes a perfect circle, an oval, and an ellipse.
  • FIGS. 11( a ) and 11( b ) are diagrams illustrating the results of the experiments for verifying the effects of stacking the sensor devices. In any of FIGS.
  • a vertical axis represents the detection signal (resistance value: S 2 ) output from the pressure sensor
  • a horizontal axis represents the pressure (mN) applied to the pressure sensor.
  • a curve C 1 in FIG. 11( a ) indicates the characteristics of the pressure sensor according to the present embodiment.
  • Curves C 2 and C 3 indicate the characteristics of Comparative Example 1 and Comparative Example 2 that are both compared with the pressure sensor according to the present embodiment.
  • the four sensor devices designed in the same manner are stacked and connected in parallel.
  • the electrode pressing material 17 is provided in each of the stacked sensor devices.
  • the protrusion end surfaces of the protrusions 17 a of the electrode pressing materials 17 are all circular with a diameter of 4 mm.
  • the electrode pressing material 17 is provided on the same single sensor device as the sensor device included in the pressure sensor according to the present embodiment.
  • the protrusion 17 a has a circular protrusion end surface with a diameter of 4 mm.
  • the electrode pressing material 17 is provided on the single sensor device.
  • the protrusion 17 a has the circular protrusion end surface with a diameter of 2 mm According to FIG. 11( a ) , in the curve C 2 of Comparative Example 1, when the pressure reaches about 3000 mN, the resistance value (resistance) hardly changes. Further, in a curve C 3 of Comparative Example 2, when the pressure reaches about 1000 mN, the resistance value hardly changes. In contrast, it was confirmed from the curve C 1 shown by the pressure sensor according to the present embodiment that the resistance value changed significantly until the pressure reached about 4000 mN.
  • FIG. 11( b ) the results of which is shown in FIG. 11( b ) , four sensor devices designed in the same manner are stacked and connected in parallel. Then, the electrode pressing material 17 is provided in each of the stacked sensor devices. The protrusion end surfaces of the protrusions 17 a of the electrode pressing materials 17 are all circular with a diameter of 2 mm
  • a curve C 4 in FIG. 11( b ) shows the characteristics of the pressure sensor according to the present embodiment described above. According to FIG. 11( b ) , it was confirmed from the curve C 4 shown by the pressure sensor according to the present embodiment that the resistance value changed until the pressure reached about 4000 mN. From the above experiments, it was confirmed that the pressure sensor according to the present embodiment had a detection range wider than that of the pressure sensor of the single sensor device because a plurality of stacked sensor devices is connected in parallel.
  • FIGS. 12( a ) and 12( b ) are diagrams for explaining the results of the experiments for verifying effects of changing electrical characteristics of the plurality of stacked sensor devices in the stack circuit.
  • the vertical axis represents the detection signal (resistance value: S 2 ) output from the pressure sensor
  • the horizontal axis represents the pressure (mN) applied to the pressure sensor.
  • a curve C 5 in FIG. 11( a ) indicates the characteristics of the pressure sensor according to the present embodiment.
  • the result of which is shown in FIG. 12( a ) four sensor devices designed in the same manner are stacked and connected in parallel.
  • the electrode pressing material 17 is provided in each of the stacked sensor devices.
  • the protrusions 17 a of the three sensor devices out of the four sensor devices have the circular protrusion end surface with a diameter of 4 mm.
  • the protrusion 17 a of the remaining one sensor device has the circular protrusion end surface with a diameter of 2 mm According to FIG. 12( a ) , it was confirmed from the curve C 5 shown by the pressure sensor according to the present embodiment that the resistance value changed until the pressure reached about 4000 mN.
  • the four sensor devices designed in the same manner are stacked and connected in parallel. Then, the electrode pressing member 17 is provided in each of the stacked sensor devices.
  • the protrusions 17 a of the two sensor devices out of the four sensor devices have the circular protrusion end surfaces with a diameter of 4 mm.
  • the protrusions 17 a of the remaining two sensor devices have the circular protrusion end surfaces with a diameter of 2 mm.
  • a curve C 6 in FIG. 12( b ) shows the characteristics of the pressure sensor according to the present embodiment described above. According to FIG.
  • FIGS. 13( a ) to 13( c ) are diagrams showing the results of theoretical calculation of a relationship between the detection signal (resistance value: S 2 ) output from the pressure sensor and the applied pressure.
  • the vertical axis represents the detection signal (resistance value: S 2 ) output from the pressure sensor
  • the horizontal axis represents the pressure (mN) applied to the pressure sensor.
  • FIG. 13( a ) is a diagram for explaining effects of connecting the stacked sensor devices in parallel. A curve C 7 shown in FIG.
  • FIG. 13( a ) shows the characteristics of the pressure sensor of the single sensor device (hereinafter referred to as a sensor device p 1 ) having predetermined characteristics.
  • a curve C 8 shows the characteristics of the pressure sensor of the single sensor device (hereinafter referred to as a sensor device p 2 ) having characteristics related to a resistance different from that of the sensor device p 1 .
  • a curve C 9 shows the characteristics of the pressure sensor in which the sensor device p 1 and the sensor device p 2 are stacked and connected in parallel.
  • a curve C 10 shows the characteristics of the pressure sensor in which three sensor devices p 1 and one sensor device p 2 are combined, stacked and connected in parallel.
  • the pressure sensors in which the sensor devices having characteristics related to different resistances are stacked and connected in parallel have a measurable pressure range wider than that of the pressure sensor of the single sensor device, regardless of the number of stacked sensor devices. Further, it can be understood that the detection signal changes more greatly when the number of stacked sensor devices is large, in a range of the applied pressure up to about 1000 mN.
  • FIG. 13( b ) is a diagram for explaining the effect of stacking the sensor devices and connecting them in series.
  • FIG. 13( c ) is an enlarged view of a region where the detection signal (resistance value: S 2 ) is low in FIG. 13( b ) .
  • a curve C 11 shown in FIGS. 13( b ) and 13( c ) shows the characteristics of the pressure sensor of the single sensor device (hereinafter referred to as a sensor device p 3 ) having characteristics related to a resistance different from that of the sensor devices p 1 and p 2 .
  • a curve C 12 shows the characteristics of the pressure sensor of the single sensor device (hereinafter referred to as a sensor device p 4 ) having characteristics related to a resistance different from that of any of the sensor devices p 1 , p 2 , and p 3 .
  • a curve C 13 shows the characteristics of the pressure sensor in which the sensor device p 3 and the sensor device p 4 , which have characteristics related to different resistances, are stacked and connected in series.
  • a curve C 14 shows the characteristic of the pressure sensor in which three sensor devices p 3 and one sensor device p 4 are combined, stacked and connected in series.
  • the pressure sensor in which the sensor devices having characteristics related to different resistances are stacked and connected in series outputs the detection signal similar to that of the pressure sensor of the single sensor device when the applied pressure is within 1000 mN.
  • the detection signal of the pressure sensor in which the sensor devices are stacked and connected in series changes with a larger inclination than that of the pressure sensor of the single sensor device, particularly in a range where the applied pressure is 3000 mN or more. From the above, it can be understood that the pressure sensor according to the present embodiment can measure a wider range of pressures than the pressure sensor of the single sensor device.
  • FIG. 13( a ) it has been found that when the plurality of sensor devices is connected in parallel, a change width of characteristics related to the resistance is larger than that of the single sensor device.
  • FIGS. 13( b ) and 13( c ) it has been found that when the plurality of sensor devices is connected in series, the change width of characteristics related to the resistance is smaller than that of the single sensor device. Therefore, the pressure sensor in which the plurality of sensor devices is connected in parallel can be said to be more preferable because a wider dynamic range can be obtained.
  • a pressure sensor including a wiring sheet, in which a plurality of sensor devices having electrodes and a conductive film disposed to face the electrodes are stacked in an arrangement direction of the conductive film against the electrodes, and a common input line for inputting electrical signals to the plurality of sensor devices, and a common output line for outputting the electrical signals from the plurality of sensor devices are formed.
  • a pressure sensor according to any one of (1) to (8), in which the plurality of stacked sensor devices is connected in parallel to each other.
  • the electrodes include a first electrode and a second electrode, and the first electrode and the second electrode are separated from each other and have a shape that can be fitted together.
  • a method for manufacturing a pressure sensor including a step of forming on a wiring sheet, sensor devices each having a plurality of electrodes and a conductive film corresponding to at least some of the plurality of electrodes, a common input line for inputting electrical signals to the sensor devices, and a common output line for outputting the electrical signals from the sensor devices, and a step of stacking the sensor devices by folding the wiring sheet.

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  • General Physics & Mathematics (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
US16/621,223 2018-04-16 2019-03-26 Pressure sensor and method for manufacturing pressure sensor Abandoned US20200200617A1 (en)

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JP2018078208A JP6839127B2 (ja) 2018-04-16 2018-04-16 圧力センサ、圧力センサの製造方法
PCT/JP2019/012849 WO2019202928A1 (ja) 2018-04-16 2019-03-26 圧力センサ及び圧力センサの製造方法

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11453362B2 (en) * 2018-07-19 2022-09-27 Posh Wellness Laboratory, Inc. Detection apparatus, seat belt, and monitoring system
US11785715B2 (en) * 2021-12-17 2023-10-10 Exro Technologies Inc. Article for power inverter and power inverter

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11493392B2 (en) * 2019-10-03 2022-11-08 Ricoh Company, Ltd. Sensor sheet, robot hand, and glove
JP7276225B2 (ja) * 2020-03-31 2023-05-18 豊田合成株式会社 センサユニット
KR20210150072A (ko) * 2020-06-03 2021-12-10 주식회사 엘지에너지솔루션 전지셀 압력 측정 장치 및 방법

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004037350A (ja) * 2002-07-05 2004-02-05 Nitta Ind Corp 抵抗型センサ
JP2007010482A (ja) * 2005-06-30 2007-01-18 Toshiba Hokuto Electronics Corp 面圧力センサー
JP5331546B2 (ja) * 2008-04-24 2013-10-30 株式会社フジクラ 圧力センサモジュール及び電子部品
CN104089737B (zh) * 2014-06-25 2015-08-05 西安交通大学 一种高灵敏度叠层式挠曲电压力传感器
JP6539204B2 (ja) * 2014-12-24 2019-07-03 日本メクトロン株式会社 感圧素子および圧力センサ
CN105865668B (zh) * 2015-01-20 2019-12-10 北京纳米能源与系统研究所 压力传感成像阵列、设备及其制作方法
WO2017058655A1 (en) * 2015-09-29 2017-04-06 Apple Inc. Pressure measurement designs
GB2549451A (en) * 2016-02-17 2017-10-25 The Helping Hand Company (Ledbury) Ltd Support evaluation device
CN107144375A (zh) * 2016-03-01 2017-09-08 鸿富锦精密工业（深圳）有限公司 高密度传感器模组

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11453362B2 (en) * 2018-07-19 2022-09-27 Posh Wellness Laboratory, Inc. Detection apparatus, seat belt, and monitoring system
US11785715B2 (en) * 2021-12-17 2023-10-10 Exro Technologies Inc. Article for power inverter and power inverter

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CN110709680A (zh) 2020-01-17
JP6839127B2 (ja) 2021-03-03

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